Two-terminal memory represents a recent innovation within the field of integrated circuit technology. While much of two-terminal memory technology is in the development stage, various technological concepts for proposed two-terminal memory devices have been demonstrated by the inventors and are in one or more stages of verification to prove or disprove associated theories or techniques. The inventors believe that various two-terminal memory technologies (e.g., resistive-switching memory, magneto-resistive memory, ferroelectric memory, organic memory, phase-change memory, conductive bridging memory, and others) show compelling evidence to hold substantial advantages over competing technologies in the semiconductor electronics industry.
In particular with respect to resistive-switching memory, the inventors believe that resistive-switching memory cells can be configured to have multiple states having respective distinct resistance values. For instance, for a single bit cell, the restive-switching memory cell can be configured to exist in a relatively low resistance state or, alternatively, in a relatively high resistance state. Multi-bit cells might have additional states with respective resistances that are distinct from one another and distinct from the relatively low resistance state and the relatively high resistance state. The distinct resistance states of the resistive-switching memory cell represent distinct logical information states, facilitating digital memory operations. Accordingly, the inventors believe that arrays of many such memory cells can provide many bits of digital memory storage.
The inventors have been successful in inducing resistive-switching memory to enter one or another resistive state in response to an external condition. Thus, in transistor parlance, applying or removing the external condition can serve to program or de-program (e.g., erase) the memory. Moreover, depending on physical makeup and electrical arrangement, a resistive-switching memory cell can generally maintain a programmed or de-programmed state. Maintaining a state might require other conditions be met (e.g., existence of a minimum operating voltage, existence of a minimum operating temperature, and so forth), or no conditions be met, depending on the characteristics of a memory cell device.
The inventors have put forth several proposals for practical utilization of resistive-switching technology to include transistor-based memory applications. For instance, resistive-switching elements are often theorized as viable alternatives, at least in part, to metal-oxide semiconductor (MOS) type memory transistors employed for electronic storage of digital information. Models of resistive-switching memory devices provide some potential technical advantages over non-volatile FLASH MOS type transistors.
In light of the above, the inventors desire to continue developing practical utilization of two-terminal memory technology.